A shift register memory has been proposed to improve the capacity of a memory. The shift register memory does not include a selection element and a data line for each memory element, but transmits data stored in memory elements to the position of a sensor or a data line. Therefore, the shift register memory has the possibility that the memory elements can be arranged with high density and the memory capacity is significantly increased.
In order to utilize this advantage, it is not preferable to provide a control electrode for each bit (each digit) in the shift register memory. Therefore, it is necessary to perform a shift operation with the desired number of digits by adding an action to all length of bit string (shift register).
However, it is not easy to shift all digit data without any error. In particular, in a case of a high-capacity memory, each shift register includes 100 or more digits, and the physical length of the shift register also must be increased. In this case, it is considered that the possibility of an operation error is increased due to the distortion of a signal waveform caused by a capacitance or inductance component.
As described above, in order to achieve a high-capacity shift register memory, a shift register is required to have high reliability such that data of each bit can be transmitted without any error by an operation on all bit string. However, it is considered that such shift operation is difficult for a conventional shift register.